A guide wire is a flexible wire, usually metallic, used to ensure the proper positioning and placement of a surgical instrument and/or implant. The use of guide wires for orthopaedic applications is well known. For example, cannulated bone screws are widely available. In use, a guide wire is inserted in the desired location, the location of the guide wire is radiographically confirmed, and the guide wire is inserted in the cannulation of the bone screw to guide the bone screw to the implantation site. Cannulated drill bits and hole taps are also available as related instrumentation to facilitate the implantation of the bone screw.
Cannulated blade plates are also widely available. A blade plate, an implant used in various surgical procedures including osteotomies and internal fracture fixation, has a blade extending at an angle from a bone plate. The blade is inserted into the bone while the plate is secured to the bone surface with screws. In some clinical situations, a chisel having a cutting member corresponding in size and shape to the blade is used to create a pathway in the bone for the blade. Although blade plates are available with blades having a wide variety of configurations, the blade (or at least the individual elements that form the blade) are flat elongated members. As a result, it is difficult and costly to manufacture a blade or a chisel with a cannulation. More importantly, forming a cannulation in the blade increases the blade size. The increased size necessitated by the cannulation and the resulting adverse consequences (e.g. stress shielding, excessive removal of bone, etc.) can be particularly problematic in the small sized blade plates which are typically used for infants, children, and adults of modest stature. Unfortunately, chisels are ordinarily used in these patient populations.
In an effort to capitalize on the benefits of guide wires yet eliminate the complications associated with cannulations, alternative implant designs have been developed. U.S. Pat. Nos. 2,222,517 and 2,239,088 and Soviet Union No. 571,255 disclose a fracture fixation nail having a groove for a guide wire. U.S. Pat. No. 2,496,126 discloses a nail/plate fixation device with webs forming a channel for a guide wire. U.S. Pat. Nos. 3,025,853 and 3,486,500 both disclose an implant that has an aperture for an introducer in which the aperture is located on a bone plate and does not extend through the portion of the implant driven into bone. U.S. Pat. No. 4,978,349 discloses a plate with a guide wire groove.
In spite of these advancements in implant design, very little has been done to improve on chisels that can be used with guide wires. Thus, there exists a need for an improved chisel and method for using a chisel in conjunction with a guide wire.